Piston for pneumatic pumps



(No Model.)

0. H.'ROBINSON. PISTON FOR PNEUMATIC PUMPS.

' No. 449,333. Patented Mar. 31, 1891.

1' moses jvwamfioz iiafklfljivbimm NITED STATES PATEN'r rricE.

PISTON FOR rusuavmrlo PUMPS.

SIPECIFIGATI'ON' forming part of Letters Patent No. 449,833, dated March 31, 1891. Application filed February a, 1891. Serial rolssoara (No model.)

To aZ Z whom it may concern:

Be it known that 1, CHARLES H. ROBINsON,

of the city of Huntsville, Walker county, in

being had to the accompanying drawings,

forming a part hereof.

My invention relates to improvements in pistons for pneumatic pumps; and it consists in the novel arrangement and combination of parts, as will be more fully hereinafter described, and designated in the claims.

In the. drawings, Figure 1 is a vertical longitudinal section of my invention. Fig. 2 is a horizontal cross-section taken on the line so a: of Fig. 1. Fig. 3 is a top plan View. Fig. 4 is a top plan view of an expanding metallic ring which I employ in carrying out my invention, and Fig. 5 is an enlarged perspective View of a wedge-shaped or expanding p ug.

The object of my invention is to construct a piston primarily designed to fulfill the conditions required of a piston in pumps for ordinary ice-machines, although it is equally applicable to other species of pumps. 7

With this end in view my invention 0011- sists in the peculiar construction, arrangement, and mode of operation of a piston in a cylinder, as I will now proceed to specifically set forth and claim.

Referring to the drawings, 1 indicates a cylinder with my improved piston located therein.

2 represents a tubular shell provided with circumferential cavities 3, inwhich any suit able packing material may be placed. The top and inner peripheral surface of said shell is provided with a circular flange 4:. The inner peripheral surface of said flange is cut away obliquely and downwardly, thereby forming an aperture 5, approximately of the shape of a frustum of a cone. Located or adapted to be located in said tubular shell 2 is a cylindrical valve 6, which valve is provided on its top surface with a projection 7. Said projection 7 is approximately of the shape of a frustum of a cone and is adapted to fit closely in the aperture 5, formed in the 4 top portion of the shell 2, which aperture forms the valve-seat for projection 7. Said cylindrical valve6 is provided in the region of its circumference with a series of perfora tions 8 for the passage of the gas. Said per forations are adapted to be closed by the inner circular flange 4 when projection 7, and consequently the cylindrical valve 6, is resting in its normal position in its appropriate valve-seat. Said shell 2 is provided in the region of its lower terminal portion with an inner circumferential recess 9, in which a circular expanding ring 10 is adapted to be inserted. Said ring is cut, and the ends where said incision is made is provided with an oblique surface, as shown in Figs. 4: and 5.

11 indicates an approximately wedgeshaped plug, which is adapted to fit between said ends and has the function of expanding and increasing the diametrical proportions of said ring 10 when the same is screwed tightly in the ends of said ring. Said plug is se-- cured to shell 2 by means of a screw 12, which passes through a suitable perforation formed in the said plug and is then screwed into said shell. The function of said ring when normally secured in the inner circular recess 9 is to hold thevalve 6 in its normal position in shell 2. Said ring 10 is of such dimensions that when the same is secured in its normal position in shell 2 it does not stop up perforations 8 and interfere with the passage of the gas. Said ring is placed in its corresponding circular recess 9 and is expanded, fitted, and normally and rigidly secured therein by means of the wedge-shaped plug 11, as hereinbefore stated and as is readily perceived by an inspection of the drawings.

13 represents a piston-rod, which is suitably secured to cylindrical valve 6, or it can be secured to said valve in any suitable and mechanical manner.

Having given an explicit description of my invention, I will -now proceed to describe its mode of operation and use. The parts are made and put together substantially as hereinbefore set forth, and it will readily be perceived by an inspection of the drawings that the piston can only compress the gas on its upward stroke. WVhen the piston is on its downward stroke, projection 7 and consequently cylindrical valve 6 are removed from Ice their appropriate valve-seats, and that removal will permit the passage of the gas,that is located below the piston, allowing itto pass upwardly above the same, and when the piston advances upon its upward stroke projection 7 and consequently cylindrical valve 6 will assume their normal position in their appropriate valve-seats, which operation will close perforations 8 and prevent the gas that is contained above the piston from finding a passage in the region below the same, consequently restraining the gas and subjecting it to the compressing effect of the piston.

Having fully described my invention, what I claim is 1. A piston consisting of a tubular shell provided with a conical aperture and an internal circular recess, a cylindrical valve provided with gas-passages and a conical projection, which projection is adapted to fit in said conical aperture as a valve-seat, and an expanding ring placed or adapted to be placed in said circular recess for retaining said valve in its downward motion or stroke in said shell,

substantially as set forth.

2. A piston consisting of a tubular shell provided with a conical aperture and an internal circular recess, a cylindrical valve provided with gas-passages and a conical projection, which projection is adapted to fit in said conical aperture as a valve-seat, an expanding ring placed or adapted to be placed in said circular recess for retaining said valve in its downward stroke in said shell, and a wedgeshaped plug for expanding and holding said ring in its normal position in said recess, substantially as set forth.

3. A piston consisting of a tubular shell provided with a conical aperture and an internal circular recess, a cylindrical valve provided with gas-passages and a conical projection, which projection is adapted to fit in said conical aperture as a valve-seat, and an expanding ring placed or adapted to be placed in said circular recess for retaining said valve in its downward stroke in said shell, a wedge-shaped plug for expanding and holding said ring in its normal position in said recess, and a piston-rod for operating said valve, and consequently said piston, substantially as set forth. In testimony whereof I affix my signature in presence of two witnesses.

CHARLES H. ROBINSON. Witnesses:

K. M. CONNOR, G. A. WYNNE. 

